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Question 1

sleep architecture

Answer 1

Sleep is divided into distinct stages characterized by different patterns of electrical brain activity. The way these patterns come together is called sleep architecture, and it changes over the course of the life span.

Question 2

Sleep cycles are 90 minutes

Question 3

Stage 1 - NREM

Answer 3

You start in Non-Rem stage, which is the lightest

Question 4

Stage 2 - NREM

Answer 4

a little deeper & harder to wake up

Question 5

Stage 3 - NREM

Answer 5

deepest stage of sleep.

If someone wakes you up in Stage 3 - you are likely to be confused, groggy, not going to understand what is going on, and will be harder to wake up

Question 6

REM sleep

Answer 6

Rapid Eye Movement - where a lot of dreaming happens.

You are close to wake, but your muscles are inhibited so that you can’t move.

Question 7

circadian rhythm

Answer 7

We get tired because of melatonin production at the end of the day, and we wake up when melatonin is decreased.

Sunlight, through our eyes is the biggest factor. Sunlight create the response to decrease melatonin production

Question 8

Homeostatic drive

Answer 8

based on how much sleep you have gotten recently.

If you haven’t got much sleep recently, it increases your Homeostatic drive, which then increases the adenosine.

If you haven’t slept for a long time, you will start producing more adenosine, and it will make you feel drowsy, and you will start falling sleep.

Question 9

negative impacts of a lack of sleep

Answer 9

1. Cardiovascular disease
2. diabetes
3. depression
4. mood disorders
5. physical performance
6. dementia

weight management
1. Ghrelin - affects appetite - you feel hungrie
2. Leptin - you feel full

if lack of sleep - Ghrelin goes up and leptin goes down

Question 10

Sleep disorders

Answer 10

1. narcolepsy - daytime sleepiness - falling asleep at random points in the day
2. Sleep apnea - snoring and stop breathing
3. Chronic insomnia - difficulty falling and staying sleep
4. Restless Leg Syndrome - twitching leg, need to get up and walk around - they can’t fall asleep

Question 11

Sleep & Aging

Answer 11

As you get older, you get less quality and less duration of sleep

• Stage 3 becomes lower and lower - it is the first you lose as you age and it is the most restorative stage of sleep

Question 12

NREM sleep

Answer 12

First three stages are grouped – non-rapid eye movement

Improves neural connections, facilitates cell restoration and repair

Question 13

Stage I

Answer 13

Short transitional phase from wakefulness to sleep

Easily disturbed by outside stimuli

May not know they have fallen asleep

Question 14

Stage II

Answer 14

Deeper than stage 1 but still a light sleep

Heart rate slows and body temperature drops

Bursts of brain activity

Stimuli from the environment can no longer reach higher level brain centres

Question 15

Stage III

Answer 15

Deepest sleep stage and most necessary for feeling well rested

Supports most restorative functions
Length of stage increases after physical activity or extended periods of no sleep

Difficult to wake up quickly – may be confused

Memory and learning can become active during stages II and III

Question 16

REM Sleep

Answer 16

Final stage of sleep

Named for the period in which the eyes move rapidly under the lids

When most dreaming occurs

Some regions of the brain are more active

Blood pressure, respiration and heart rate rise – skeletal muscles are inhibited from contracting

Question 17

Sleep Cycles

Answer 17

First cycle through the three stages of NREM sleep

Followed by a period of REM sleep (always a final stage)

Sequence lasts about 90 min – may go through four or five cycles

Slow-wave sleep are longer in the first part of the night

More REM in the latter part of the night (dreaming)

Question 18

Circadian Rhythm Variation

Answer 18

Genetics determines a night owl or morning lark

Morning people do better in the day but tire earlier – more sensitive to sleep loss

Evening people perform better in the evening and handle sleep loss better

Encounter external stimuli – zeitgebers – can influence our master clock

These can be activity, exercise, eating and the most important is light

Question 18

Circadian Rhythm

Answer 18

Sleep wake pattern coordinated by the suprachiasmatic nucleus (SCN)

Every cell has a sleep wake pattern dictated by DNA – SCN coordinates them all

Night is the circadian rest phase

Insufficient sleep disrupts the repair and regeneration tasks

Question 19

Circadian Rhythm affected by Light

Answer 19

Direct connection to the SCN via the eye

Exposed to light in the morning at a certain time regularly, causes the SCN to set the internal clock to wake up at the same time

Develop sleep habits naturally regulated

Can also reinforce unhealthy behaviour – light late at night the SCN will reset – delay sleep phase

SCN can also cause the pineal gland to secrete melatonin at dusk – preparation for sleep

Blind persons often have a difficult time with sleep due to the lack of light stimulation

We are exposed to unnatural sources of light undermining the reliance on the sun’s 24 hr cycle

Blue light produced by electronics is most disruptive and can affect sleep

Question 20

Circadian rhythm disruptions

Answer 20

Jet lag – internal clock is set to a new environment
Experience falling asleep and waking at appropriate times
Can cause nausea and loss of appetite
Delayed sleep phase – person stays up until 4 am and sleeps until noon – if having to wake up earlier – the switch may be difficult – dysfunctional

Question 21

Homeostatic sleep drive

Answer 21

Pressure to sleep in relation to the amount of sleep you have had in relation to wakefulness

Circadian rhythm works in opposition to the homeostatic drive

Thought to be mediated by the neurochemical adenosine

More time spent awake – more adenosine –promotes sleepiness

Sleep clears this from the brain

Question 22

Caffeine Blocks Adenosine in the Brain and Delays Homeostatic Sleep Drive

Question 23

How the two systems work together

Answer 23

Interact in a complex process of mutual opposition

Pressure to sleep is driven by the homeostatic sleep drive and directly related to how much sleep you have gotten and how long you have been awake

The circadian rhythms are not influenced by time asleep or awake – occur at the same time each day

Work independently from one another – promotes sleep and wakefulness

Question 24

Changes in Circadian Rhythm

Answer 24

Most prominent changes across the life span are circadian rhythm changes

Children need to go to bed earlier than adults

Insufficient sleep can interfere with attention and learning

Change in adolescence, stay awake at night and sleep late in the morning

Sufficient sleep in this group aids in affecting grades and moods positively

High school and post-secondary students show a sleep deficit of 1 – 3 hours on school nights
——Sleep longer on weekends

Almost 2/3 of this group are getting poor sleep

Question 25

Changes in Circadian Rhythm (2)

Answer 25

School start times force students to rise during their biological night – results in serious sleep deprivation

Sleep is important for higher order thinking, problem solving, reasoning and good judgement

School districts having implemented later start times found a decrease in tardiness, absences, drop out rates, school nurse visits and car accidents

Studies have shown that there may be a substantial economic gain by delaying school start times

Mistakenly associate toughness and discipline with sleep duration

Circadian rhythms shift away from the ‘night owl’ tendency in the twenties

Question 26

Sleep Cycles, Age and Sex

Answer 26

As we age, the duration and quality of sleep decrease

Children are the hardest to rouse – slow wave sleep and greater threshold for transition from sleep to wakefulness may explain why more children sleepwalk

Late twenties we enter less deep sleep
Late 40s, 60-70% is gone, by 70 has decreased by 80-90%
Women show less sleep disruption than men

As we get older, we wake up more easily
Lighter stage of sleep – more sensitive to external stimuli

Question 27

Sleep Cycles, Age and Sex (2)

Answer 27

Age reduces the time spent in restorative sleep and diminishes the number, amplitude and intensity of deep-sleep brain waves

May also be linked to neurodegeneration

Women report more instances of insomnia and men report more snoring
—-More likely to be diagnosed with sleep apnea

Women may be subject to sleep disruption due to hormonal changes during menstruation, menopause and pregnancy